Rotary pump machine



Jly 9, 1929.

w. J. STERN 1,720,577

ROTARY PUMP MACHINE Filed April s, 1927 4 Sheets-Sheet l July 9, 1929. 4w. J. sTERN- r1.720.577

ROTARY PUMP MACHINE Filed April 8, 192'? 4 sheetssheet 2 July 9, 1929.w. J. STERN 1.720.577

ROTARY PUMP MACHINE Filed.Apri1 8, 1927 4 ShQets-Sheec 3 July 9, 1929.w. J. STERN 1,720,577

ROTARY PUMP MACHINE Filed April 8, 1927 4 Sheets-Sheet 4 Patented Jury9,1929.

UNITED STATES 1,720,577 PATENT OFFICE.

WILLIAM JOE STERN, OF LONDON,A ENGLAND, ASSIGNOB TO POWERPLUS LIMITED,OF LONDON, ENGLAND, A COMP! NY INCORPORATED IN GREAT BRITAIN.

ROTARY ruin MACHINE.

Application tiled April 8, 1927, Serial No. 182,042, and in GreatBritain April 24, 1928.

This .invention comprises improvements in and connected with rotary pumpmachines and is concerned with pump machines of the co-called crescentchamber class. In .this class of pump machine the piston or rotor is aneccentrically mounted body formed with spaced slots for vanes to workin,k these slots being in some cases fitted with oscillatory trunnionblocks formed with slots in which the vanes have a sliding movementrelative to the rotor. In using these machines as pumps or compressors,it is generally ad Vantageous to drive the rotor, the vanes beingengaged with centric means such as a lay shaft.

In the specification belonging to my prior Patent No. 1,616,285, I havedescribed constructions according to which .the varies were fitted withso-called thrust members, these members being advantageously in the formof i'ib members adapted for stiifcning the Yanes and for taking thestresses due to the reaction between the piston body and the vanes.

The object of the present invention is to lighten the construction ofthe vanes while at the same time enabling them to withstand variousstresses to which they are subjected in the operation of these machines,for it is of the utmost importance to have vanes of the lightestpossible construction so as to rcduce friction losses.

According to this invention, the vane blades are provided on each facewith a series of ribs of small thickness but of relatively great depthso as to resist bending of the blade, the ribs being also adapted, ifdesired, to take up centrifugal stresses. The ribs are advantageouslyconstituted by thin metal plates which may be slot-ted centrally to titon to the blades and be formed with base or ring portions foroperatively connecting them with the centric means.

In order to enable the invention to be readily understood, reference isdirected to the accompanying drawings, in which Figure 1 is a transversesectional elevation of a rotary compressor embodying improvements inaccordance with this invention.

Figure 2 is an irregular longitudinal section of the compressor, takenon the line II-II of Figure l.

Figure 3 is an elevation of a piston vane assemblage,

.Figure 4 is a sectional side elevation of Figure 3.

Figure 5 is a plan view of a suitable form of oscillatory trunnion blockfor use with the piston varies.

Figure 6 is a cross-sectionon the line VI--VI of Figure'.

Figure 7 is a perspective view illustrating a modilied form of pistonvane assemblage.

Figure 8 is a perspective view of a moditied construction of vane rib. AFigure 9 is a fragmentary sectional view, illustrating the practicalapplication ofthe form of vane rib shown in Figure 8, and

Figure 10 is a Iplan section of a trunnion rocker and Ivane bladeshowing the application ot intermediate bearing members as hereinafterreferred to.

In Figures 1 and 2, a is the outer casing of the compressor formed withinlet and eX- haust ports or ducts b and c respectively and d is thepiston bodyor rotor mounted eccentricall in the outer casing upon ballbearings e an f. g is the rotor shaft which runs in the bearing e and isdriven from the power shaft It through a coupling z'. The bearing f issupported by a hollow shaft or sleeve j with flange at one end forsecuring it in the casing a. Z is a stub shaft which may be secured'iinone end of the rotor in alignment with the rotor shaft g, this stubextending through the sleeve j and being revolubly supported at theother end by a ball bearing m mounted in the casing a. Upon the sleeve jis keyed a supporting member a for the inner race of a ball bearing owhich constitutes a centric revoluble bearing for the piston varies p ofthe machine. A screw g may be provided as an additional securing meansfor the member n, and the vanes p, as is usual in these machines, havesliding en, gagement with the slots of cylindrical roclfr-y ers ortrunnion blocks such as 1' mounted in longitudinal recesses or slots s-in the rotor body and revolubly supported at the ends in ball bearingst in the ends of the rotor.

The machine illustrated in Figures 1 and 2 has four piston varies butthere may be only two or any other desired number greater than two. Therib members u which are fitted to the vane blades in accordance withthis nvention suitably consist of thin metal plates, which may be steelstampings of a size 3/8 x .104 in tranverse section for a vane blade of.064 thickness. By reference also to Figures and 4, in which a vaneblade is marked lv, it will be'seen that these rib plates areadvantageously in the form somewhat of an inverted T, so as to provide abase part or foot` u. The rib plates are used on the vane blades inpairs. Only one pair is used for each blade in igures l to 4, and eachpair is secured one on each side of a. vane foot member w by means ofscrews a: passing through the foot or base u of the plates. The vanefeet w comprise arcuate parts y for engaging the inner periphery of a.blade ring e in the manner hereinafter described. The rib plates u areslotted as at 1 for the reception of the vane blades. It Will be seenfrom Figure 4 that the slots 1 are slightly longer than the radial widthof the yvane blades and that the slots extend from apoint on a levelwith the top or outer surface of the arcuate parts y of the vane feet toa point situated at a short distance from the outer extremity ef the ribplates. The vane blades are notched as at 2 at points spaced apart adistance equal to the distance between the rib plates and it will beseen that a vane blade may have the rib yplates applied thereto bypassing same through the slots 1 of the plates until the notches 2 comeinto line with the rib plates. Thereupon, the vane blades can be moved0utwardly, so that the solid portions 3 at the extremities of the ribplates are engaged with the notches2, and when the rib plates have beenscrewed to the vane feet, upon tightening a grub screw 4 in the vanefoot, the blade is heldiirmly in position in the rib plates which thusvserve effectively as blade supports or cradles.

In assembling the pump machine, the vanes are engaged in the slots ofthe rockers 7 of the rotor and the vane feet are engagez? with slots inthe bladering e aforesaid as will be described.

For convenience of-manufacture, the oscillatory cylindrical trunnionblocks may be made in halvesfthat is divided longitudinally, as seen forexample in Figures 5 and 6, and held together by ferrules, caps orequivalent devices at the ends or by their spigot ends 5 engaging withthe inner races ot the ball bearings t aforesaid as shown in Figure 2.The'slots 6 of the trunnion blocks are enlarged at the places where therib members u pass through and preferably the enlargements are made longenough to extend over a pair of rib members as seen by way of example at7 in Figure 5. The purpose of this is to provide a'space between the ribplates 'for 'the mounting of rocking bearing members or pads of therocking type, as shown at 8 Figures l and 2. Boththe vane blades and therib plates or vane cradles have a running tit in the trunnion slots 6,and the vane blades take a bearing on the bearing members 'which areable to rock in the enlargements 7 or" the slots 6, with the movementsof the venes, because assembling the vanes in the machine, the

blade ring .e the inner race ofthe ball bearing 0 being driven on to asuitably machined part of the supporting member fn aforesaid and theouter race fitting centrally within the ring z. There are four slots 10,and when the vanes are in position with the arcuate parts y engaged withthe inner periphery of the ring z as seen in Figure 2, an end cap 11 isscrewed on to the blade ring to keep the parts in position. The ballbearing 0 is held by-distance rings 12 and a spigot ring 13 of eccentricform which is finally fixed in position secured to the supporting membern. The interior of the blade ring z may be supplied with lubricantthrough a duct 14 and the blade feet may have ducts 15 formed therein toallow lubricant to pass under the action of centrifugal force to thechannels between the rib plates u and so to the rocking .bearing members8 in the trunnion blocks r. The vane feet A are of sufficient dimensionsto overlap the slots 10 in the blade ring .e and in conjunction with theouter race of the ball bearing 0 prevent escape of lubricant throughthese slots.

If the vane blades be made of suitable material, the bearing pads 8 canbe allowed to bear on them direct as shown Aand the combination of eachpair of rib plates with the blade portion between the members of eachpair constitutes a sort of H girder forming a modified construction ofthrust member of the nature hereinbefore referred to. Should the vaneblades 'be of material unsuitable for bearing purposes, bearing platesmay be inserted between the bearing pads 8 and the blades are passedinto T form slots 10 in the.

vane blades v as will be understood withoutfurther illustration. Thesebearing plates could be made integral with the rib plates by machiningthe combination out of the solid.

The general operation of the machine will be understood withoutfurtherdescription7 but it may be mentioned that as the rotor, in

revolving, carries the vanes round in the casing. the rib plates willprevent any bending of the vane under the peculiar stresses to which thevanes are subjected in this type of machine, while at the same time theywill also take up the bearing pressures of the vanes upon the bearingpads 8 under the accelerative and decelerative action of the vanes.Furthermore the rib plates restrain the vane blades against centrifugalstresses which are taken up by the blade ring z through the vane feet.

The blade ring, in conjunction with the arcuate parts of the vane feet,oder a space on either Iside of the ball bearing o constituting a commoncentre from which lubricant can be nion blocks.

The modification illustrated in Figure 7 is suitable for adoption in thecase of blowers or other rotary pump machines of relatively greatlength. nly part of thevane assemblage is shown and it will be seen thatthe rib plates 16, in this case, have their feet perforated forvengagement with rods 17 extending between a pair of vane feet, one onlyof which is shown at 18. The vane blades 19 are of similar constructionto those previously described, but the slots in the rib plates terminateat the inner end in screw threaded holes adapted to receive grub-screws20 for retaining the blades in position. These rib plates are disposedalong the blades in pairs with suitable intervals betweenv the pairs (asin Figure 10 for example) and the vane feet have arcuate parts 21adapted to engage in Vthe known grooved rings'revoluble on ball-4bearings mounted centrically in the pump casing, as shown for example inFigure 1 of the drawings of my Patent No. 1,616.285. Distancing sleeves22 may be employed for spacing apart the inner ends of the rib platesupon the rods 17.

The construction of rib member shown in Figure 8 is applicable for use.in cases where the vanes revolve about a sleeve or shaft mountedcentrically in the outer casing. as disclosed for instance in my priorPatent No. 1.616,285. The feet of the rib plates 22 in this constructionare in the form of ringshaped parts 23, adapted to encircle the sleeveor shaft. The plates are used in pairs as shown in Figure 9 and when thevanes arepto be mounted to revolve onball bearings on a centric shaftone rib plate is pinned or otherwise secured on each side of the outerrace of a ball bearing 24 mounted on the shaft which tance between theouter surfaces of each pair of ribplates. Instead of having notches itwill also be understood that t-he spacing between the thin metal ribplates may be determined by suitable distance pieces which mav also beadapted to form a sealing tip as will be understood without furtherdescription.

Figure 10 shows how the rib plates marked 27, lmay be arranged in pairsalong the length of a long blade 19 as hereinbefore referred to. Thisfigure also disclosesthe provision between the different pairs of ribplates of intermediate bearing pads 8a. The use of these intermediatepads may sometimes be` advisable in the case of very long blades andthey may be arranged so as to-come into operation only in thel case ofemergency, that is to say, if the vane blades bend unduly. Y.

In the construction shown in Figures 1 and 2 1t 1s not essential toemploy a single blade i'ing suchas z. For instance, two separate i ringsindependently mounted on anti-friction bearings and grooved forengagement with the arcuate parts y of the respectivevane i feet, may beused. Arrangement may also'be made whereby the single blade ring, whenemployed, may be mounted on two ball bearings instead of one as shown,the object `being to prevent any likelihood of the ring becoming canted.The single ring would be positively driven at rotor speed,-When used, asby the rollers 28, mounted on the ring taking.

into holesv29 in the adjacent end of the rotor, but if two independentlymounted rings be,

used it is not necessary to arrangel for them y to be positively driven.

1. A rotary pump machine comprising a' casing, a piston body mountedeccentrically in said casing, centric means in said casing, vane bladesarranged in `slots of said piston body and engaged with said centricmeans, rib members of small thickness and relatively great depthdisposed on said blades to resist bending thereof andhaving a runningclearance in saidslots, and bearing surfaces for the ,blades in saidslots in the vicinity of said 'rib members, substantially as set forth.g

2. A rotary pum machine comprising a casing, a piston bo y mountedeccentrically in said casing, centric means -in said casing, vane bladesarranged in slots of said piston body and engaged with said centricmeans,

thin metal reinforcing plates fitted on vsaid blades at right angles tothe plane thereof and having a running clearance in said slots,

and bearing surfaces for the blades in said slots in the Vicinity ofsaid reinforcing plates, substantially as set forth.

3. A rotary pum machine comprising a casing. a piston bo y mountedeccentrically in said casing, cent-ric means in said casing, vane bladesarranged in slots of said piston body and engaged with said centricmeans,

rib members fitted on saidvblades and comprising thin metal platesslotted centrally to t on to the blades said rib members having arunning clearance in said slots and bearcasing, a piston' body mountedeccentrically in said casing,centr1c means in said casing, vane bladesarranged in slots of said piston body and engaged with said centricmeans and having spaced notches in their outer edge,

rib members fitted on said, blades and comprising thin metal platesslotted to fit over the blades but having an unslotted part at theirouter extremity to engage in said notches of the blades, said ribmembers having a running clearance in said slots and bearing surfacesfor the blades in said slots in the vicinity of said rib members,substantially as set forth.

5. A rotary pump machine comprising a Casin a cylindrical rotor mountedeccentrical y in said casing, vane blades arranged in slots of saidrotor, centricmeans in said casing, rib members of small thickness andrelatively great depth disposed on said blades to resist bending`thereof, and adapted for connection'to said centric means, said ribmembers having av running clearance in said slots and bearing surfacesfor the blades in said slots in the vicinity of said rib members,substantially as set forth.

6. A rotary pump machine comprising in combination a casing, acylindrical rotor mounted eccentrically in said casing, vane bladesarranged in slots of said rotor, rib members of thin metal platedisposed on said blades to resist bending thereof, and havingbase'portions at their inner extremity, vane feet operatively connectedWith said base portions, a ring revoluble centrically in said casing andadapted for operative engagement with said vane feet, said rib membershaving a running clearance in said slots, and bearngsurfaces for theblades in said slots in the vicinity of said rib members, substantiallyas set forth.

7. A rotary pump machine comprising a casing, a cylindrical rotormounted eccentrically in said casing, vane blades arranged in slots ofsaid rotor, vane feet comprising' arcuate parts, rib members fitted onsaid blades to resist bendin thereof and constructed for connection withsaid vane feet, a blade ring member centrically mounted in said casingand formed with circumferentially spaced slots for engagement with therespective vane feet which are retained by said arcuate parts thereof,and means for positively driving said ring member at rotor speed,substantially as set forth.

8. A rotary pump machine comprising a casing, a cylindrical rotormounted eccentrically in said casing, vane blades arranged in slotsofsaid rotor, a blade ring member centrically mounted in saidcasing, andlformed with circumferentially spaced slots, and means for positivelydriving said ringmemberv at rotor speed, vane feet engaged with theslots of said ring member and comprising arcuate parts 0f .Suchdimensions as to overlap the slot openings circumf-"rentially, and ribmembers fitted on said bladfs to resist bending thereof and constructedfor connection with said vane feet, substantially as set forth. n

9. A rotary pump machine comprising a casing, a Cylindrical rotormountedeccentrically in said casing, vane blades arranged in slots of saidrotor, a blade ring member with circumferentially spaced slotscentrically mounted in said casing on an anti-friction bearing device,means for driving said ring member at rotor speed, vane feet of saddleform to straddle said bearing device and comprising arcuate parts forengaging said ring member at the slots thereof, and rib members fittedon said blades to resist bending thereof and constructed for connectionwith said vane feet, substantially as set forth.

10. A rotary pump machine comprising a casing, a piston body mountedeccentrically in said casing, centric means in said casing, vane bladesarranged in slots of said piston body and operatively connectedwith'said centric means, rib members dis osed in pairs on said blades,and individual bearing members of rocking pad type, disposed in therotor slots between the members of each pair of rib members,substantially as set forth.

11. A rotary pump ,machine comprising a casing, a piston body mountedeccentrically in in pairs on said blades and individual bearl ingmembers of rocking pad type, disposed in 'the slots of said bearingblocks between the members of each pair of rib members, substantially asset forth.

12. A rotary pump machine comprising a casing, a piston body mountedeccentrically in said casing, vane blades arranged in slots in saidpiston body, and individual rocking bearing members of short lengtharranged at isolated points in said slots to provide bearing surfacesfor the vanes only at selected points of their length. v

13. A rotary pump machine comprising a casing, a piston body mountedeccentrically in said casing, centric means in said casing, rockingbearin blocks arranged in slots of said piston bod vane blades arrangedin slots of said bearing blocks and operatively connected with saidcentric means, rib members disposed in pairs on said blades, rockingbearing members disposed in the slots of said bearing blocks between themembers of each pair of rib members, and additional rocking bearingmembers disposed in the slots of said bearing blocks intermediatelybetween respective pairs of rib members, substantially as set forth.

14. A rotary pump machine comprising a cylindrical casing, avcylindrical rotor mounted eccentrically in said Casing, Cylindricalrocking bearing blocks mounted in slots of saidv rotor, a slotted bladering member mounted to revolve Centrieally on anti-friction bearings insaid casing, vane blades arranged in slots of said rocking bearingblocks, rib members of thin metal plate arranged in pairs on said vaneblades to resist bending thereof, vane feet connected with said ribmembers and comprising arcuate parts adapted to engage said blade ringmember and of such dimensions as to overlap the slots thereof, androcking bearing members disposed in the slots of said bearing blocksbetween the members of each pair of ribV members, ducts being formed insaid Vane feet leading from the space within the blade ring member tothe channel between the members of each pair of rib members,substantially as set forth.

` WILLIAM JoE STERN.

